1. Field of Invention
The present invention relates to a projector that projects an image.
2. Description of Related Art
In general, a projector that projects a color image includes an illumination optical system that causes illumination light to exit therefrom, a color light separation optical system that separates the illumination light into three color illumination light beams, three light valves that convert (modulate) the three color illumination light beams into light beams that correspond to color signals that correspond to the three color illumination light beams, respectively, a color light synthesizing optical system for synthesizing the converted (modulated) three color light beams that exit from the three light valves, and a projection optical system that projects an image that is represented by the synthesized light beam that exits from the color light synthesizing optical system. Electro-optical devices, such as liquid crystal panels, are used as the light valves. Hereafter, a projector including three light valves for three colors is referred to as a three-plate-type projector.
It is preferable for an image that is projected by a projector to be bright, and desirable for the illumination light beams to efficiently illuminate light-incident surfaces of the light valves. Therefore, conventional projectors exist that adjust the size of illuminating areas of the illumination light beams by adjusting the projection magnification of the illumination light that exits from the illumination optical system.